Hmmm....somehow I don't buy it. In order to jump to
PR 7, there must be a least a number of high quality one-way backlinks which is PR6 pointing to the site itself.
Another thing is that how is the person going to maintain 30 domains at one go? It's not going to gain any
PR (even
PR 1) by just registering to some directories.
PR algo is much more complicated and fool proof than that.